Contents

This document demonstrates how to troubleshoot a Cisco Voice Gateway 200 (VG200) that runs Cisco IOS® Software Release 12.1(5)YH4 configured as a Digital Signal Processor (DSP) Farm that does not register with Cisco CallManager. The VG200 configured as a DSP Farm has a finite set of DSPs. If the configuration exceeds the resources of the DSP then the transcoder and conference bridge do not register. This document shows the process you use in order to troubleshoot this problem.

Note: The problem this document describes is not applicable for other Cisco IOS Software releases. This problem has been fixed in Cisco IOS Software Release 12.2(13)T. This is when the dspfarm command support was first integrated in the mainline. In Cisco IOS Software Release 12.2(13)T and later, Cisco IOS does not allow the user to configure the transcoder and the conferencing sessions more than the available DSP resources on-board.

The information in this document is based on these software and hardware versions.

Cisco CallManager version 3.2(2a) or Cisco CallManager version 3.3.3

Cisco IOS Software Release 12.1(5)YH4 which has the support for DSP Farm

Cisco VG200 Gateway

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

This section is true for the DSP Single In-line Memory Modules (SIMMS). The High Density Voice Network Modules (NM-HDV) Farm module ships with two SIMMS and is able to handle three additional SIMMS. Each SIMM contains three DSPs. Each DSP supports four transcoding sessions or one conference bridge. Four transcoding sessions are supported for 729-711. If you use the Global System for Mobile communication (GSM), then the DSPs can handle three transcoding sessions. Therefore, the maximum number of transcoding sessions that a five-SIMM configuration supports is 60 transcoding sessions. The maximum number of conference calls that a five-SIMM configuration supports is 15.

Problem

The DSP Farm is configured and the Media Access Control (MAC) address in Cisco CallManager is added to properly register the transcoding and/or conferencing resources. However, within Cisco CallManager the devices display as 'not registered'. When you reboot the VG200 and/or stop/start the Cisco CallManager service, it has no effect. This output typically is a result of a configuration issue on the VG200.

Note: Make sure the TCP port number 2000 is open between the conference stations. Firewalls or access-lists can block TCP port 2000 which is used by SCCP or Skinny clients (IP phones).

This window appears from the Cisco CallManager:

In order to start to troubleshoot, verify within the configuration the number of DSPs that you need. When you look at the relevant portion of the configuration of the DSP Farm, you are able to gather this information:

In total, thirteen DSP resources on board are required. You can verify the available on board DSP resources when you issue the command test dsprm 1 where the number 1 refers to the slot number in which NM-HDV module is installed. The Verify the Number of DSPs Installed section explains this.

Solution

While you configure DSP Farm, verify the on board DSPs with the test dsprm command and configure the Conference bridge and transcoder sessions accordingly. Never configure more than the available resources although the affected Cisco IOS Software release allows you to do so.